An axial flow regulator is provided by the American Meter Division of Singer Company. This equipment typifies an axial flow regulator. Briefly, this flow regulator incorporates a flange supported housing fitting in a pipeline. In the flange, there are ports for introducing fluid under pressure to expand a sleeve. A sleeve is clamped so that the outer face of the sleeve is exposed to fluid under pressure. This is to force the sleeve to expand. The sleeve expands radially inwardly to throttle an annular flow space around a central barrier. The central barrier is a somewhat streamlined plug positioned axially in the passage which diverts the fluid flow into the annular space adjacent to the sleeve. An important reason for equipping a regulator to flow less than 100% is to keep from having to install an oversized and expensive relief valve, i.e., the relief valve must be able to handle the full open capacity of the regulator.
The axial flow regulator exemplified above and others of different manufacture all have a 100% rating. The 100% rating is typically related to the size of the device. It is difficult to obtain devices with a different 100% rating. This difference of course flows from the fact that they are typically manufactured in just a few sizes. In the field, the device must often be throttled. A nominal six inch rated axial flow regulator must, at full opening flow, pass a smaller flow compared to the nominal rating for the device. In this circumstance, the axial flow regulator must be reduced in size. This is difficult except if one choses to manufacture a specially dimensioned version. That is costly to obtain.
This apparatus is an insert which fits within the axial flow regulator to modify the flow of the regulator. In other words, it defines a reduced full open flow capacity. Moreover, the restricter of this disclosure can be modified easily in the field by the simple expedient of drilling more holes in it. The capacity of each hole of a given size is fixed and predictable.
The restricter of this disclosure is an adaptive fitting which cooperates with and seats against an axial flow regulator. This restricter can be obtained in predrilled or blank form, subject to be drilled in the field. In blank form, it will pass no fluid. However, in the field, the 100% capacity required of the axial flow regulator can be determined and suitable holes drilled in the blank to obtain the carefully tailored restrictive capacity required. This apparatus thus incorporates a surrounding sleeve which shoulders against the axial flow regulator and which blocks the annular flow space through it. Accordingly, a standard axial flow regulator which can be readily obtained off the shelf at supply stores can then be adapted to have a 100% capacity which matches a value less than the manufactured capacity. The reduced flow capacity then becomes the maximum capacity of the device. Moreover, the restricter of this disclosure enhances the structural support of the central streamlined plug or barrier which induces the flowing fluid to divert into the annular regulated space.
Should it be necessary to change the capacity of an axial flow regulator in the field, the device of this disclosure can be readily drilled on the spot with a number of small holes. Through the use of suitable charts, the flow capacity of the reducer of this disclosure can be determined and modified in the field. Moreover, such modifications can be accomplished without dismantling the pipeline other than to obtain access to the downstream side of the axial flow regulator.
The present apparatus therefore has one object, namely the modification of axial flow regulators. The restricter of this disclosure is manufactured in blank by manufacturing a central member within a cylindrical sleeve or surrounding skirt which anchors the equipment in place. The transverse central member is built to conform with and seat against the axial plug which diverts the fluid flow into the annular flow space where the flow is regulated. Usually, the restrictors are pre-drilled to give a capacity specified by the customer at the time of order.
This device is further summarized as being an adapter in which a selected number of holes can be readily drilled to specify the 100% flow capacity of the device.